Shaped rod turbulence generators for use in a flowing stream of paper pulp



D. PARKER ETAL SHAPED ROD TURBULENCE GENERATORS FOR USE IN A FLOWINGSTREAM OF PAPER PULP Nov. 30, 1965 7- Sheets-Sheet 1 Filed Oct. 5 1962INVENTORS L/OSEPH D. PARKER BY JOHN E SCHMAE/VG a/A ATTORNEYS Nov. 30,1965 J. D. PARKER ETAL 3,220,919

SHAPE ROD TURBULENCE GENERATORS FOR USE IN A FLOWING R PULP STREAM OFPAPE 7, Sheets-Sheet 2 Filed Oct. 5, 1962 LP /6a.

C I 2555 LL INVENTORS JOSEPH D. PARKER BY JOHN E SCHMAENG A TTORNEYS 31965 J. D. PARKER ETAL 3,220,919

SHAPED ROD TURBULENCE GENERATORS FOR USE IN A FLOWING STREAM OF PAPERPULP Filed 001;. 5, 1962 7. Sheets-Sheet 5 L-3OO W 314 pain-W, mi

doss u D. PARKER BY JOHN E SCHMAENG W 2 K /%0RNEYS Nov. 30, 1965 J D.PARKER ETAL 3,220,919

SHAPED ROD TURBULENCE GENERATORS FOR USE IN A FLOWING STREAM OF PAPERPULP '7 Sheets-Sheet 4 Filed Oct. 5, 1962 INVENTORS dosEPH D. PARKER WBY JOHN FSCHMAEA/G I l 2 g TZTTORNEYS 3,220,919 N A FLOWING Nov. 30,1965 J. D. PARKER ETAL SHAPED ROD TURBULENCE GENERATORS FOR USE I STREAMOF PAPER PULP TSheets-Sheet 5 Filed Oct. 5, 1962 INVENTORS Nov. 30, 1965J. D. PARKER ETAL 3,220,919

SHAPED ROD TURBULENCE GENERATORS FOR USE IN A FLOWING STREAM OF PAPERPULP fSheeias-Slxeet 6 Filed Oct. 5, 1962 S R m use m m? E W H O I 0 C T.5 T O A H fix E O S J @w W Nov. 30, 1965 J. D. PARKER ETA 3,220,919

SHAPED ROD TURBULENCE GENERATORS FOR E IN A FLOWING STREAM OF PAPER PULPFiled Oct. 5. 1962 7 Sheets-Sheet 7 Xf/i/ 'IL INVENTORS JOSEPH D.PAFPKEP BY JOHN EScHMAEA/G United States Patent Ofilice 3,220,919Patented Nov. 30, 1965 SHAPED ROD TURBULENCE GENERATORS FOR USE IN AFLOWING STREAM OF PAPER PULP Joseph B. Parker and John F. Schmaeng,Beloit, Wis.,

assignors to Beloit Corporation, Beloit, Wis., a corporation ofWisconsin Filed Oct. 5, 1962, Ser. No. 228,621 3 Claims. (Cl. 162343)This invention relates to the handling of fiuid slurries, and moreparticularly, to the maintenance of desirable fiber dispersion in stockslurries for paper making and the like processes.

Prior attempts to establish uniform distribution of fibers in the stockslurry and to maintain fiber distribution, once established, along theflow path or stream in the headbox prior to deposition of the stock onthe forming surface have involved employment of such complicatedauxiliary equipment as perforated rotary rolls, commonly referred to asrectifier rolls, holey rolls, or silencing rolls, and other mechanicalvibrating, shaking and stirring devices, all of which induce turbulentflow currents of large amplitude in the slurry.

A major disadvantage attendant use of such prior art devices resides inthe tendency of the fibers to form clots, flocks, or agglomerationswhich, when deposited on the forming surface, result in undesirablelocalized irregularities of high density in the forming Web. In someinstances, such clots and the like break down the web, therebyinterrupting production.

By employment of the present invention, we eliminate the requirement forrotary, vibrating or other moving auxiliary means in the headbox andprovide for delivery of the stock slurry to the forming surface of apaper making machine under conditions of substantially uniform meanvelocity, minimum large scale flow turbulence, and minimum grosssecondary fiow patterns wherein the fiber distribution and dispersion inthe liquid vehicle are substantially uniform, thereby permittingformation on the forming surface of a web having substantially uniformdensity and fiber distribution throughout. The practice of the presentinvention also substantially reduces the formation of undesirable clots,flocks or agglomerations in the turbulent stock.

It is, therefore, an important object of the present invention toprovide an improved method and apparatus for effecting the desireddistribution of particulate material in a liquid vehicle, such as thefibers in paper making stock or slurry.

Another object of the instant invention is to provide an improvedapparatus for distributing particulate material in a liquid vehicle,comprising a plurality of first means extending transverse to a liquidvehicle flow path for generating small scale turbulence in the liquidvehicle to distribute the particulate material therein, and a perforatedmember upstream from said first means converting the liquid vehicleunder pressure into a plurality of high speed jets flowing through theperforations of the member in the direction of said first means.

Yet another object of the instant invention is to provide an improvedmethod of distributing particulate material in a liquid vehicle,comprising generating a plurality of jets in a stream of such vehicle,generating successively smaller scale turbulence in the streamdownstream from the jets to distribute the particulate material therein,and effecting controlled amplitude of the turbulence in the stream stillfurther downstream to increase distribution of the particulate materialtherein.

Other and further objects, features and advantages of the presentinvention will become apparent to those skilled in the art from thefollowing detailed disclosure thereof and the drawings attached heretoand made a part hereof.

On the drawings:

FIGURE 1 is an elevational view with parts broken away and parts shownin section of a headbox for a paper machine embodying the instantinvention;

FIGURE 2 is an essentially diagrammatic cross sectional top plan view ofa headbox comparable to that shown in FIGURE 1 (but of smaller width),taken generally along the line IIII of FIGURE 1, and for the sake ofsimplicity not showing the exact dimensions of the embodiment of FIGURE1;

FIGURE 3 is an elevational view comparable to the view of FIGURE 1 butshowing another embodiment of the instant invention;

FIGURE 4 is another elevational view comparable to that of FIGURES 1 and3 but showing still another embodiment of the instant invention;

FIGURE 5 is another elevational view comparable to FIGURES l, 3 and 4but showing still another embodiment of the instant invention;

FIGURE 5A is a fragmentary detail view showing a modification of theembodiment of FIGURE 5;

FIGURE 6 is a detail sectional elevational view showing an essentialpart of another headbox embodying the instant invention;

FIGURE 7 is a plan view taken substantially along the line VlI-VII ofFIGURE 6 with parts shown in section;

FIGURE 8 is still another elevational view comparable to that of FIGURES1, 3, 4 and 5 showing a different embodiment of the instant invention;

FIGURE 9 is an enlarged fragmentary sectional elevation of the centralportion of the slice approach shown in FIGURE 8;

FIGURE 10 is a view comparable to that shown in FIGURE 9, but showing amodified arrangement;

FIGURE 11 is a fragmentary detail sectional elevation of a single rod,with parts broken away and parts shown in section;

FIGURE 12 is an enlarged section of the rod shown in FIGURE 11 takensubstantially along the line XIIXII; and

FIGURE 13 is an enlarged sectional view of a rod comparable to FIGURE12, but showing a different cross sectional structure for the rod.

As shown on the drawings:

In FIGURE 1 there is indicated generally by the reference numeral 10 apaper machine hea-dbox having a generally triangular cross sectiondefined by a generally horizontal bottom wall 11, a generally verticalback perforated wall or plate 12 receiving a stock stream under pressureindicated generally at 13 and a top wall 14 swingably mounted on theback wall 12 to define a slice 15 with the bottom wall 11. The top wall14 is inclined downwardly (about 10 from horizontal) toward the slice15, so that the top wall 14 and the bottom wall 11 define a headboxchamber A that is tapered toward the slice 15. The chamber A is atapered approach to the slice opening 15 for flowing a stock stream(filling such tapered approach A) in a generally (average) rectilineardirection D which may be assumed to lie in a plane bisecting theapproximate angle C of 10 between the top wall 14 and bottom wall 11.

The chamber A contains a transversely extending, first multiplicity orbank of transversely (i.e., cross-streamwise) spaced abutments or rods16 (e.g., 16a, 16b, 16c, 16d in FIGURE 2) each extending substantiallycompletely across (transversely depth-wise) the stock stream, which aremounted for swingable movement with the top wall 14 (being secured atthe top of the rods 16, by suitable bolts or the like, not shown). Itwill be seen from FIGURE 2 that these rods 16 are positioned ingenerally at 17 in FIGURE 1 are secured in like manner to the top wall14 for swingable movement therewith and these second abutments or rods17 (Le, 17a, 17b, etc.,

in FIGURE 2) are positioned completely across the stock streamdownstream from the first bank of rods 16, but upstream from the slice15. The first bank generates substantially uniform small scaleturbulence of a first order of magnitude, whereas the second bank 17 ispositioned in the turbulence wakes of the first bank 17 to minimizecollection of fibers, etc., on the faces of the rods 17, which generatesubstantially uniform smaller scale turbulence of a second order'ofmagnitude.

Additional and similar, successive, downstream banks of rods 18, 19, 20and 21 are shown in FIGURE 1 with the down-stream-most bank of rods 21still being spaced from the slice 15, and the rods in the succession ofbanks 16 through 21 are generally formed of successively smallerdiameters with successively smaller transverse spacing therebetween. Itwill be noted that only the first three banks 16, 17 and 18 arerepresented in FIGURE 2, again for purposes of simplifying thedisclosure of the function of these banks of rods which will bediscussed in detail hereinafter. "As is indicated generally in FIGURE 1,the stock is pumped from a fan pump or suitable device P for generatinga stream of stock under pressure through a main cross stream headerindicated at 30, from which the stock under pressure rises through aplurality or relatively long narrow generally parallel risers 31, whichalso extend across the full width of the machine. These risers 31 feedinto the bottom of an inlet compartment 32 in which the stock from thevarious risers 31 is merged into a main stock stream 13 flowing at acomparatively slow flow rate under substantial pressure and this mainstock stream flows against the perforate plate 12 where at the stream isconverted to lower pressure, high speed jets flowing out of theperforations. As indicated in FIGURE 2, the perforations in the plate 12include rows extending in the cross machine direction, such as the row12a, 12b, 12c, 12d (only 12d of which being shown in FIGURE 1), and asshown in FIGURE 1, the perforations in the plate or back wall 12 extendalso in generally vertical columns, such'as the perforations 12d1, 12dand 12d2. Immediately at the off-running side of each column, such asthe column 12d,1 12a and 1202 there is positioned a rod 16d from thefirst bank 16 of rods, so that a jet of stock from each of theseperforations will impinge upon the rod or abutment 16d and willimmediately undergo an abrupt change in direction (thereby keeping theoperating face 16d1 clean).

The chamber 32 and approach A are operated full of stock. It will thusbe seen that the stock flows through the submerged perforations in theback plate 12 and through the entire slice approach A under pressure andout the slice onto a forming wire W of the conventional Fourdrinier typetraveling around a breast roll 33 in conventional fashion.

A plurality of pedestals indicated at 34 secured to a fixed support suchas the floor F carry a cross frame 35 having a plurality of uprights35a, 35b, 35c and 35d. A floor or bottom wall portion 11a of the overallbottom wall 11 is secured to the top of the uprights 35b, 35c 35d bysuitable means such as the welds indicated, for fixed. mounting of thegenerally. horizontal floor portion 11a. The back wall 12 is, likewise,fixed and rigidly mounted to the back of the floor wall 11 and the rearupright 35d by suitable means such as welds or the like.

The headbox 10 is, of course, provided with side walls only the rear oneof which 36 is indicated at the back of the headbox chamber A in FIGURE1, but in FIG- URE 2 the other wall 37 is also indicated. The side walls36 and 37 have side frames secured thereto, only one of which isindicated in FIGURE 1 generally at 38. The side frames 38 carry pivotsone of which is indicated at 39 which swingably mount an upright frameportion 14a of the top wall 14 (about the pivot 39, and about the rearwall 12 which is, of course, rigid with the side frame 38. Aconventional roof lift device 40 carried on the side frames 38 andoperating a lift cable 41 connected via a pivot 42 to the side frame 14aof the top wall 14 is used to swing the top wall 14 from the positionindicated in FIGURE 1 to the phantom position also shown in FIGURE 1wherein the top wall is indicated in the primed numbers. It will beappreciated that the banks of rods indicated by the primed referencenumerals 16 through 21 are likewise moved with the top wall 14 into thephantom position shown in FIGURE 1 when it is desired to open up theheadbox 10 for maintenance, cleanup, or other sutdown operation.

In this respect, it will be noted that the downstreammost banks of rods20 and 21 are anchored to an apron ing a part of the support frame 35,so that the apron piece 50 may define the forward or off-runningcontinuation 11b of the floor wall 11a.

There is a slight space 53 between the floor w-all' sections 11a and 11bwhich feeds into a chamber defined by a base plate 35 for the crossframe 35, the two uprights 35a and 35b and the forward portion of thewall portion 11a. These elements form a cross chamber B which is used tohelp purge the headbox chamber A of any dirt or particulate materialwhich might tend to lie along the bottom thereof. This purge chamber Bis functional during operation of the machine and a swingable damper 54pivoted to the bottom of the floor wall 11a and adjustable in positionby a set screw assembly 56 of conventional structure. It will beappreciated that this floor slot 53 with stock flow control means in theform of the damper element 54, will permit a very slow flow purging ofheavy materials from the stock during operation, or it will permit afast flow recirculation of stock :beneath the floor 11 at this positionand back by conventional means to the stock system.

The side frame 14a for the top wall 14 has an upper extension 1412,which carries the cable pin 42 with attached cable 41 (whichelements aremounted at both sides of the machine) and it also carries at its forwardend a cross bar or pivot 60. Bell crank arms 61 pivotally connected at62 to a slice adjusting jack or hydraulic motor 63 pivotally connectedat 64 to the frame 14b are used for delicate slice control of a forwardslice plate 65 that is secured to and pivotal about a rotatable bar 66.A plurality of conventional adjusting screws 67, are operativelyconnected to the forward end of the slice plate 65 and a pivot bar 68 inthe bell crank 61. The slice adjusting jacks 63 will thus provide formaximum adjustment of the position of the slice plate 65 and theadjustable screws 67 provide for delicate adjustment thereof.

The cross bar 60 also pivotally mounts a frame element 70 presenting anarcuate face 70a for sliding engagement with a contiguous arcuateportion 14c at the forward end of the top wall 14, so that slidingmovement of the arcuate face portion 70a may move the cross bar 66 to alimited extent toward and away from the slice 15. The limited movementof the cross bar 66 of course results in limited movement of the sliceplate 65; and movement of the arcuate element 70a is effected by asecond hydraulic motor 72 pivotally connected to the frame 70 at 73 andpivotally connected to the top wall side frame 14!) at 74. The sliceadjustment elements indicated by the 60 and 70 series of referencenumerals are all carried on the cross bar 60 which in turn is carriedwith the top wall 14 during swinging movement thereof.

Referring in greater detail to the rod banks 16 through 21 within theheadbox chamber A, it will be seen that the rod banks 16 through 19 arenot secured to the fixed floor portion 11a and instead terminateimmediately adjacent thereto with slightly rounded ends. The rod banks16 through 19 are also not in exact vertical alignment, instead beingtilted about off vertical (i.e., at an angle X of about 95 to the streamdirection D) in the direction of stock flow. The rounded ends plus theangle of tilt for the rod banks 16 through 19 afford unusual advantagesin self-cleaning of these devices during operation. In fact it has nowbeen found that the upstream or operating faces of rods (such as therods 16 through 19) extending at a downstream slant from one wall 14 toclosely spaced relation from the opposite wall 11 preferably arepositioned to define an obtuse angle with respect to the planes of bothwalls 11 and 14, and more specifically, an obtuse angle X of about 95 to135 with the general flow direction D.

Referring specifically to FIGURE 2, it will be seen that each of therods, such as the rod 16d has a generally circular cross section whichis preferred, although it will be appreciated that the invention alsocontemplates the use of rods having other cross sectional shapes such asthat of a polygon (e.g., triangular, rectangular, etc.), and theinvention also contemplates the use of turbulence generators other thanbanks of rods, which include grids, slotted plates or the like, but ineach case there should be certain fundamental open areas and otherstructural characteristics. For example, it is important that thestructure used employ a substantial multiplicity of abutments, rods orother structures presenting turbulence generating land areas (e.g., suchas the upstream face 16a1 of the rod 16d) between open areas A-1 and A-2accommodating stock flow for generating a first substantially uniformpattern of small scale turbulence of a first order of magnitude in thestock stream. For this purpose, it will be noted that the rod 16d hasthe preferred generally rounded upstream side or face 16d1 and that italso terminates abruptly at the downstream side 16d2, such abrupttermination being contrasted to an elongated teardrop shape which wouldresult in streamline flow past the rod 16a. The abrupt termination atthe downstream face 16d2 results in turbulence generationdiagrammatically indicated in the upper portion of FIGURE 2 as beingcharacterized by a low pressure area LP at the immediate downstream sideof the rod 16a, and wakes W, W trailing along the side edges of the rod16a at the off-running side. Since the stock stream in this region isnot exposed to air at the surface, the creation of such turbulence evenat high operating speeds does not tend to draw air into the stock. Itwill be noted that each of the rods in the first bank 16 has acomparatively large diameter D4, which for practical purposes may rangefrom about A of an inch to about 1 /2 inches, but which is about 1%inches in the embodiment shown in FIGURE 2. The perforations 12a through12d in the plate 12 preferably have a diameter that is within the rangefrom about /2 of the diameter D-l to about equal to such diameter D-1,and in the preferred embodiment here shown the diameter of theperforations 12a, etc., is about 1 nch. This produces a submerged jetwhich serves to effectively clean the operating or upstream face of eachof the rods in the banks 16.

The center-to-center dimension M-l between ad acent rods 16b and 160 inthe first bank 16 is preferably equal to about twice the diameter D1,which would give a total open area in the rod bank 16 of approximately50%. The open area in the rod bank 16 may, however, range from apractical minimum of about 25% to a practical maximum of about 75%, sothat the ratio of M-l to D-1 may range from about 3 to 1 to 1 to 3.

It will also be noted that the first bank of rods 16 is spaced upstreamfrom the second bank of rods 17 a distance L-l (from center-to-centerbetween the rod banks 16 and 17). The second rod bank 17 is located soas to receive the turbulence generated by the first rod bank 16 inpartial decay. The distance L-1 is approximately equal to about 2 toabout 5 times the center-to-center spacing M-l in the first rod bank 16,since it is found that maximum intensity of the flow turbulence appearsto occur from about 2 to about 4 times the distance M-1 downstream ofthe rod bank 16, depending upon the overall average velocity of thestock stream, which is another factor that must be considered inselecting the preferred distance L1. At distances from the first bank 16greater than those just indicated for the distance L-l, the turbulentflow generated in the stock by the rods 16 tends to dissipate or decayand to merge into a substantially uniform means flow pattern. Thus thesecond bank 17 is located a distance L-1 downstream from the first bank16, such distance L-l being greater than the distance of the zone ofmaximum intensity of the first order of flow turbulence created in theslurry by the first bank of rods 16 but less than the distance from thefirst bank of rods 16 to a region where uniform mean flow occurs.

It will further be noted from FIGURE 2 that the spacings L-l, L-2, etc.between the rod banks 16, 17, 18, and the space between the first bank16 and the perforated plate 12, each afford a region of abruptlyincreased crosssectional area intermediate each such turbulencegenerating cross-machine extending surface elements 16, 17, 18, etc.,which in turn provides a region (e.g., of preferably 50% open area) ofabruptly decreased cross-sectional area in the stock stream, whereby thestock in the stream is subjected to a primary relatively gradualvelocity increase via the converging or tapered alignment of the top andbottom walls 14 and 11 (FIGURE 1) plus superimposition of a successionof sequentially decreasing turbulence-generating zones (such as thezones or sequences S S S S of FIGURE 2) which involve abrupt crosssectional area diminuition followed by abrupt increase to superimposesecondary cyclic stock velocity acceleration followed by deceleration ateach such sequence S 3: S2: 1-

The rods 17 of the second bank are substantially smaller in diameter D-2and the center-to-center spacing M-2 is also substantially smaller,sothat each of the rods 17 such as the rod 17x presents a turbulencegenerating land area 17x1 that is substantially smaller in size than theturbulence generating land area 16d1 of the first bank 16 and that ispositioned between smaller open areas such as A-3 accommodating stockflow through the rod bank 17, for generating a second substantiallyuniform pattern of smaller scale turbulence in the stream, and ofturbulence of a second order of magnitude in the stream. The second bank17 thus receives the initially induced first order eddy currents in astate of partial decay from the first bank 16 and converts the same intoa substantially greater number of second order eddy currents which arelesser in magnitude than the first order eddy currents; and such secondorder eddy currents tend to further disperse and distribute the fibersthroughout the stock while the amplitude of the second order eddycurrents is reduced relative to the amplitude of the first order eddycurrents. The upstream face portions of the rods 17 (such as the faceportion 17x1) are kept clean by virtue of the fact that they are exposedto the trailing wakes from the first rod bank 16. Such turbulenceagainst the operating faces of the rods 17 tends to reduce or minimizestapling or the collecting of fibrous elements on the upstream surfacesof the rods 17.

The third bank of rods 18, shown in FIGURE 2, is composed of rods ofstill smaller diameter D-3 in a bank having still smallercenter-to-center spacing M-3 between the rods 18, which are againtransversely spaced between the side walls 36 and 37 extendingcompletely across between the side walls 36 and 37. The rod bank 18 isalso positioned so as to be positioned in the wakes generated by the rodbank 17 while still in a condition of partial decay, and the rod bank 18is spaced downstream from the rod bank 17 a distance L-2 which ispreferably within the range of about 2 to about 5 times thecenter-to-center spacing M 2 in the rod bank 17.

Another aspect of the instant invention involves spacing thedownstream-most rod bank from the slice opening a distance within therange of about 3 to about 7 times the center-to-center spacing betweenthe rods or'abutments in the downstream-most rod bank. Thus, if theembodiment of the invention shown in FIGURE 2 is assumed to employ therod bank 18 as the downstreamrn-ost rod bank in a headbox having a sliceopening S-l indicated diagrammatically by a dotted line, when therod'bank 18 should be spaced upstream from the slice opening S 1 adistance L-3 which should be within the range of about 3 to about 7times the center-to-center spacing M-3 in the rod bank 18. In likemanner, referring to FIGURE 1, it will be appreciated that thedownstream-most rod bank 21 should be spaced from the actual sliceopening 15 a distance that is within the range from about 3 to about 7times the center-to-center spacing between the rods in'the rodbank 21.

It will thus be seen that in a final quieting zone X (FIGURE 2) ofpartial turbulence decay and of a longitudinal or downstream-wisedimension X of at least a plurality of the longitudinal dimensions ofthe immediate upstream sequence S is provided between planar smoothconvergingly tapered walls. Although it will be understood that even theplain walls of the quieting Zone X have some (nominal) shear-effectturbulence generation upon the stock stream flowing past this zone X thezone X essentially provides for partial decay of turbulence generatedand secondary velocity change eifects generated in theturbulence-generating rod banks 18, 17, 16.

Another important aspect in the instant invention resides inthediscovery that although the turbulence generating land areas (i.e.,the rod diameters here shown) in successive downstream rod banks shouldbe reduced successively in size for successive generation of smaller andsmaller scale turbulence, there is a practical minimum diameter for thedownstream-most rods or abutments using a given type of paper makingstock. Thus this minimum diameter may be smaller for extremely shortfiber stock, but for most stocks the practical minimum diameter is aboutto /2 inch. Downstream-most rods of approximately this size turbulencegenerating land areas have been found to carry out the desired functionof the headbox with minimum practical collection of fibers or staplingof strings that may have formed elsewhere in the stock system. In viewof this, it will be appreciated that the intermediate rod banks, such asthe rod banks 17 shown in FIGURE 2, will have rods of diameters D-2significantly larger than the downstream-most rods 18 and significantlysmaller than the diameters D-1 of the upstream-most rods 16. In theoverall arrangement of FIGURE 1, this is also true, so that the rods inthe banks -17, 18, 19 and 20 and successively smaller diameters, withthe diameters of the rods in the bank 20 being larger than those in thebank 21, and the rods in the bank 21 having the minimum practicaloperating diameter previously described.

With respect to the open areas in the various rod banks, 'in generalpractice an open area of approximately 50% 8 in each of the successiverod banks is preferred, although the open areas in the rod banks may bewithin the previously recited range of about 25% to about Referring nowspecifically to FIGURES 3, 4 and 5, it will be seen that parts showntherein corresponding in function and/ or structure to parts previouslydescribed in FIGURE 1 are designated by the same reference numeral inthe 300 series in FIGURE 3, in the 400 series in FIG- URE 4 and in the500 series in FIGURE 5.

In FIGURE 3 the tapered approach A300 to the slice 315 contains thesuccessive turbulence generating rods 316 through 321, generallyconforming to the sizes, spacing and structure previously described,except that in FIGURE 3 the'rods are all substantially vertical and aresecured to both the top and bottom walls 314 and 311 for greaterstructural strength. The same is true of FIGURES 4 and 5, although theoverall alignment of the tapered approaches A400, A400 and A500 isdifferent to accommodate different machine structures and the use ofdifferent stocks.

The headboxes 310, 410 and 510 are also diiferent from the headbox 10 ofFIGURE 1, in that they are operated with the maintenance of a stocklevel L-300, L-400 and L-500 in each that is subjected to controlled airunder pressure in a conventional pressurized headbox structure, with aconventional level control, as the level control pipe LC shown inFIGURES 3, 4 and 5, for control of the levels L300, L-400 and L-500 inaccordance with the structure and arrangement shown in greater detail inUS. Patent No. 2,509,822. Conventional sight glasses 301, 401 and 501are employed for the convenience of the operators. 1

One essential difference between the headboxes of FIGURES 3, 4 and 5 andthat of FIGURE 1, is that the perforated plate 12 in FIGURE 1 isarranged so as to impinge jets directly upon the first bank of rods 16,whereas different structures are used in the headboxes 310, 410 and 510.Referring specifically to FIGURE 3, it will be seen that stock from asuitable source is fed into a tapered header aligned in cross machinedirection and designated only in FIGURE 3 only by the large diameterinlet 302 and the comparatively smaller diameter outlet 303 of thetapered header, which feeds the stock in a cross machine direction withrespect to a generally horizonally, transversely aligned perforatedplate 312. The pressure in the incoming stream of stock forces the stockto change direction abruptly and converts the stock stream into aplurality of generally closely spaced high speed submerged jetsimpinging upon a first bank of transversely spaced rods 304 in generallyparallel alignment with the plate 312. The impingement of the submergedjets upon the rods 304 (which have the relationship and diameter,spacing, etc., relative to the perforations 312av through 312e alreadydescribed in connection with the structures 12 and 16 of FIGURE 1),results in dispersion of the fibrous particles in stock and the creationof substantial small scale turbulence in the stock at the off-runningside of the rod bank 304. The stock then is forced (under thepressurized head in the headbox 310) through a right angle turn and intothe tapered approach A-300 while the stock still is in a condition ofdecaying turbulence. The advantage of the use of the headboxes 310,410'and 510 is that entrained or trapped air in the stock being fed intothe headboxes has an opportunity to escape into the pressurized air zoneabove the levels in each just prior to entrance into the taperedapproaches in each of such headboxes.

InFTGURE 4, the stock is again fed in cross machine direction into thebottom of the headbox 410 at 402, from which the stock stream isconverted into a plurality of high speed submerged jets passing throughthe perforated plate 412. In the headbox 410, it will be seen that theperforated plate is more closely spaced to the first bank of rods 416 inthe-tapered approach A400, so the use of a bank of rods comparable tothe bank of rods 304 shown in FIGURE 3 may be optional (with certainmore easily dispersed stocks) for purposes of obtaining adequatedispersion of the fibers prior to entrance into the tapered approachA-400.

In FIGURE 5, the stock is again fed into the bottom of the headbox incross machine direction through an inlet 502, and then converted to aplurality of high speed submerged jets passingthrough the perforationsin the plate 512. The high speed jets passing through the perforationsof the plate 512 impinge upon a headbox wall or bafiie 550, whichresults in an abrupt right angle turn in the stock fiow and the furtherdispersion of the fibers in the stock. The stock then flows in arelatively high degree of small scale turbulence upwardly, then throughanother right angle turn and into the tapered approach A500. Asindicated in FIGURE 5A, however, at certain operating speeds and usingcertain stocks, it may be advisable to modify the structure of theheadbox of FIGURE 5 to the extent of including a perforated plate 512Aat the mouth of the tapered approach, so that it may function to impingeclosely spaced high speed submerged jets against the upstream-most bankof rods 516 in the tapered approach A-500, much in the manner describedin connection with the cooperating function between the perforated plate12 in the first bank of rods 16 in FIGURE 1.

Another feature of the arrangement of FIGURE 5A involves the simplifiedmounting for the rod bank 516T. As indicated, the rod bank 516' iscomposed of a plurality of generally cylindrical hollow rods integralwith an upper base plate 516A and a lower base plate 516B extending thefull width of the approach A500'. The plates 516A and 5168 presentgenerally rounded smooth surfaces to the flow stock within the inlet,and are seated in transversely extending grooves 514A and 511B in thetop and bottom walls 514' and 511, respectively, so that the assembly ofthe rod bank 516' may be slid through transverse motion in and out ofposition in the inlet. The rod bank 516 is retained in position in theinlet A500 during operation by means of through bolts such as the boltsB516 extending through the top wall 514', the first rod shown of thebank 516, and the bottom wall or floor 511' to receive a nut N-516 onthe threaded lower end of the bolt B-516 for securing the rod bank 516'in position. The rod bank 517 is mounted in like fashion (although thespecific features of the bolt arrangement are omitted for the purposesof simplifying the disclosure). The hollow rod and bolt arrangement thusdescribed in connection with FIGURE SA has a number of advantages, inthat it provides for added structural strength for the inlet A-500'(which is operated under substantial pressure), while also providing forease of assembly and disassembly in the manner indicated. Thisparticular type of mounting affords distinct advantages in the case ofthe larger upstream rods in the practice of the invention, since theserods have rather substantial turbulence generating .areas of such widththat they do not ordinarily tend to collect fibers or strings(particularly when the submerged jets of stock are impinged upon theoperating faces). In the case of somewhat smaller rods, however, therehave been found distinct advantages in using the tilted rod arrangement,one embodiment of which having been described in connection with certainof the rod banks of FIGURE 1 and another, and the most preferredembodiment which will be described in connection with FIGURE 8.

Referring now to FIGURES 6 and 7, it will be appreciated that thearrangement shown therein is a modification of the perforated plate andimmediately adjacent bank of abutments (312 and 304) already describedin connection with FIGURE 3. In FIGURE 7 it will be seen that the bankof transversely extending rods 604a through 604e, alphabetically,extends across the upwardly flowing stock stream (although notnecessarily from wall to wall completely in this arrangement for thereason 1% that subsequent banks of abutments are contemplated asindicated in the tapered approach A-300 of FIGURE 3). The perforatedplate 612 contains rows of perforations 612a, 612b, 6120, 612d and 612::which are spaced to extend transversely of the stock stream in onedirection and each of such rows has a plurality of spaced holesextending transversely of the stock stream in general alignment with thetransversely extending rods, as at the perforations 612e1, 612122, 612e3and 612e4 which are mounted to impinge submerged jets of stock againstthe rod 604e. The diameter of the perforations 612a etc. is equal to orslightly less than the diameter of the rod 604, etc., as previouslydescribed. Although the rods of the 604 series are of rather substantialdiameter, i.e., about one inch, so that they do not have a tendency tocollect fibers or strings on the operating faces thereof at reasonablyrapid stock flow velocities, the impingement of the submerged jets fromthe perforations of the plate 612 has the net effect of substantiallyeliminating any collection of fibers or strings on the operating facesof these rods, while simultaneously creating a particularly satisfactorydispersion of the fibers in the stock through the impingement effect.This thus creates an initial dispersion of satisfactory character, plusoff-running turbulence from the rod bank 604 that is small scaleturbulence, but which is reduced to still smaller scale turbulence bypassage past the successive banks of successively smaller rods havingsuccessively smaller stock flow spaces therebetween, with eachsuccessive downstream rod bank receiving turbulent flow from theimmediate upstream rod bank that has not completely decayed into uniformflow, so that such turbulent flow may serve to assist in minimizing thecollection of fibers or strings on the operating faces of the rods ineach of the successive downstream banks. In this way the finaldownstream bank or banks may comprise comparatively smaller rods ofdiameters as little as /8 of an inch to /2 of an inch, so that suchdownstream-most banks may impart the desired very fine scale turbulenceto the stock at their off-running sides while still having the upstreamturbulence impinging thereon of sufficient turbulent character tominimize collection of fibers and strings on such comparatively smalldiameter rods.

Referring now to FIGURE 8 it will be seen that still another embodimentof the instant invention is shown wherein elements of substantially thesame type and function as those previously described are designated bythe same reference numerals in the 800 series. It will be appreciated,however, that the embodiment of FIGURE 8 shows what is currentlybelieved to be the superior embodiment of the invention in a number ofrespects. It will be appreciated that the previously describedembodiments of the invention have utility with respect to one particulartype of stock or another and often with respect to a plurality ofdifferent types of stock, but the embodiment of FIGURE 8 has been foundto be superior to the previously described embodiments, at least withrespect to certain commercial paper making stocks, for the reasons whichwill be described in detail hereinafter.

In general, the headbox 810 is provided with a perforated transverselyextending plate 812 receiving stock under pressure (for example as shownin the embodiment of FIGURE 1), and successive rod banks 816, 817, 818,819, 820 and 821 again having the general overall transverse spacing,successively diminishing transverse spacing, successively diminishingrod sizes or abutment generating area sizes, successive spacing betweenthe rod banks, etc. shown in the corresponding rod bank series in FIG-URE 1. With respect to the open areas in the various rod banks in FIGURE8, the preferred open area is approximately 50% in each of thesuccessive rod banks 816 through 821, although open areas in the rodbanks may vary within the previously recited range of about 25% to about75%. As in the case of the previously described perforated plates 12,etc., the perforated plate 812 has a generally smaller open area (forsubmerged jet generation) that is at least about /2 of the open area ofthe upstream-most rod bank 816 and is preferably within the range ofabout 5% to 15% open area (with the best results apparently beingobtained using about to 12% open area.

As shown in FIGURE 8 the tapered approach A-800 is defined generally bya horizontal floor 811 and a top wall 814 inclined about 10 from thehorizontal, so that the overall angle C8 between the top and bottomwalls 814, 811 is about 10. In practice, the angle of the taperedapproach may vary from a minimum effective angle of about 5 to a maximumeffective angle of about 25". In any case, the approximate average flowdirection of the stock D-8 is presumed to bisect the angle C8 forpurposes of simplification and reference to the angle of tilt of therods in the banks 818 through 821.

In essence, the rods 816 and 817 in the upstream-most two banks aremounted in substantially the manner described in connection with FIGURE5A for the convenience of assembly and disassembly and the addedstructural strength advantages already described. The perforated plate812 is preferably mounted in relatively closely spaced relation to thefirst rod bank 816 so as to effect the desired impingement of thesubmerged jets upon the rods in the bank 816, at a distance S ofpreferably about one to two times the perforation diameters in the plate812,- although the operating range for the distance S may include aslittle as about /2 of the perforation diameters and as much as aboutfour times the perforation diameters, in the preferred arrangement suchas that shown in FIG- URE 8 wherein the submerged jets are actuallyaimed at the turbulence generating faces of the rods in the bank 816.

It will also be noted that preferably in the case of the smaller sizerods 818 through 821 in the downstream banks it is particularlyadvantageous that the rods extend at a downstream slant or tilt from onewall (here the top wall 814) to closely spaced relation from theopposite wall (here the fioor wall 811) and provide in each case aslanted or tilted upstream face 818a through 821a. The slanted faces818a, etc., preferably form an obtuse angle X-8 with the average flowdirection line D-8 and (of course, also form a slightly larger'obtuseangle X-8a with the headbox wall 814 on which the rod bank 818 ismounted). Although the minimum dimension for the angle X8 may be aslittle as about 95, as indicated in FIGURE 1, it has been found thatdistinctly superior results are obtained if the angle X-8 issubstantially greater and the angle X-8 may be as great as 135. Also,this angle may advantageously be increased slightly in successivedownstream rod banks. As indicated in the embodiment 811), the rod bank818 comprises a plurality of transversely spaced rods secured to asuitably formed transversely extending base plate 818A which may be fitin a recess 81413 in the top wall 814 for ease of assembly anddisassembly and it is secured thereto by a plurality of bolts one ofwhich is indicated generally at B818. The rod banks 819, 820 and 821 aremounted in similar fashion.

Referring now to FIGURE 9 for a more detailed analysis of thearrangement of the rod banks 819, 820 and 821, it will be seen that therods in each of these banks terminate with rounded ends closely spacedfrom the floor 811 a distance T of about inch, so that any strings orfiber flocks which may have been formed upstream and not broken up orredistributed will not be able to collect on the turbulence generatingfront faces 819a, 820a, 821a. Instead, there will be no addedaccumulation of fiber on the slanted turbulence generating faces andwhatever strings or other undesirable elements that may have reached therod banks 819 through 821 will not be stapled on to the rods in thislocation for collection of additional fibers and will instead slip downand off the rounded ends through the small spaces T so as to causeminimum imperfections in the ultimately formed paper web. For thispurpose, the obtuse angle of slantX-9 for the turbulence generating face819a in each of the rods of the rod bank 819 is preferably about (and itmay preferably range from about 110 to The obtuse angle X40 for the nextdownstream bank 820 is preferably about the same, whereas the obtuseangle X-11 for the downstream-most bank 821 is preferably a still largerobtuse angle of about 120. The angle X-11 has been found to bepreferably about 5 to 15 greater than the angle X-9 or X-lti; and theangle X-11 is preferably within the range of about 110 to about 130. Aspreviously indicated the line D-8 bisecting the angle C8 of about 10 isused for reference purposes.

It will also be noted that the floor 811 in FIGURE 9 is provided withgrooves 811E and 811F which are filled with cross bars 809E and 809E",respectively, so as to provide a smooth floor for engagement with thestock stream. As indicated in FIGURE 10, however, the cross bar 809E isreplaceable with the base plate 820a for the rod bank 820, so that therod bank 820 may be mounted from the floor wall 811 rather than the topwall 814 in the manner shown in FIGURE 10, and the top wall groove 814Emay be filled with the blank or cross bar 809E so that the top wall willpresent a smooth continuous surface to the stock stream. The cross bar8MP may obviously be used for the same purpose with respect to the rodbank 819. It will be appreciated that in the arrangement shown in FIGURE10, the turbulence generating upstream faces 820a for the rod bank 820define an obtuse angle X-12 of approximately 110 with the center fi'owline D-8, so that the turbulence generating faces 820a are thus slanteddownstream at approximately the same obtuse angle X-12 as the obtuseangle X-10 indicated in FIGURE 9. The advantage of the arrangement shownin FIGURE 10 is that any possible channelling of flow along a wall faceand/ or loss in turbulence generation and/ or rectification effected bythe small spaces T between the rounded ends of the rods and the oppositewall face would be erased by having alternate rod banks 819 and 821extending from opposite wall faces as indicated in FIGURE 10. Otheradvantages from the arrangement of FIGURE 10 will be apparent withrespect to the desirability of obtaining uniformity in turbulencegeneration throughout the stock stream while at the same time obtainingthe desired advantages of employing rod banks or abutments wherein theelements extend only from one of the tapering walls 811 or 814 toclosely spaced relation from the other wall.

Still another particularly important aspect of the instant inventionresides in the discovery of a unique configuration for a turbulencegenerating surface or face for a rod or similar abutment which furtherassists in avoiding the possibility of having fiber or strings or thelike stapled or entrapped by the rod. This embodiment of the inventionis shown in detail in connection wth FIGURES ll, 12 and 13. FIGURE 11represents a single rod R which may, for example, be one of the rods inthe rod bank 821 shown in FIGURES 8, 9 and 10, and the rod R would thusbe mounted on a base plate 821a seated in a suitable groove in the topwall 814 and having its turbulence generating face F slanted at anobtuse angle of X-13 (of approximately from the top wall. The turbulencegenerating slanted (upstream face F on the rod R) has a groove G thereinwhich is tapered slightly in the region of the base plate 121A, butwhich is substantially uniform in depth down to the rounded end E forthe entire length of the front face F on the rod R. It has been foundthat this groove is unusually satisfactory in avoiding the tendency forstrings to collect and/ or be stapled upon the rods in the rod bank.

Although it is not desired to limit the invention to any particulartheory, attention is directed to FIGURE 13 which shows a cross sectionalview of an ordinary cylindrical rod R with an upstream turbulencegenerating face F about which is wrapped a fiber string H having twotrailing ends H and H which tend to become entangled in the staplingprocess. The stock stream flow is in the direction indicated by thearrow ST. It will be appreciated that when the central part H of thestring is finally in contact with the turbulence generating roundedfront surface F of the rod F, the velocity component of -the stringportion H becomes approximately 0, whereas the pressure with which thestream urges the string portion H against the turbulence generating faceF' reaches a maximum. It will be seen that the dotted line I shown inFIGURE 13 plots the impingement pressure along an assumed abscissa (x);whereas the points on the abutment generating surface F are plottedalong an assumed ordinate (y). It will thus be seen that the maximumpressure J is obtained opposite the central part of the turbulencegenerating face F at H but at about 33 above or 33 below the point H(for example at the point H the impingement pressure is indicated asapproaching zero. It will thus be seen that when a string such as thestring H hits the rod R at approximately its mid point H the draggingeffect of the stock stream on the tWo trailing ends H and H is notappreciably different and with a maximum compressive pressure J there isa tendency for the string H to remain on the face of the rod R. It willbe appreciated that the angle of tilt or angle of slant X (hereinbeforedescribed) will serve to create a slight velocity component parallel tothe rod axis, so that slanting surface for the turbulence generatorsdoes assist in moving strings along the rod surfaces before substantialadditional fiber particles are collected thereby. The improvedturbulence generating surface F shown in FIGURE 11 and shown in FIGURE12 in greater detail, however, is distinctly superior from the point ofivew of eliminating the creation of the situation whereby the centralportion of the string H is subjected to a maximum impingement pressurecomponent 1 As indicated in FIGURE 12, the groove G on the frontturbulence generating face F of the rod R precludes the sticking of thecentral portion H of a string H to the front surface of the rod R by theapplication of maximum impingement pressure (i.e., J in FIGURE 13).Instead, the central groove G is so formed that the central portion H ofthe string H will not even come in contact with the solid surface of therod R. The central portion H of the string H will thus not be stabilizedin position on the front face of the rod R and in this unstable positionthe string H tends to slip off the face F of the rod much more easily inordinary stock fiow.

It will be understood that modifications and variations may be effectedwithout departing from the spirit and scope of the novel concepts of thepresent invention.

We claim as our invention:

1. In a tapered approach to a paper machine slice opening defined byconverging top and bottom walls for flowing a stock stream filling suchtapered approach through the slice opening and on to a formin surfacecomprising a first multiplicity of spaced generally cylindrical rodsextending from one of said walls substantially the depth of the stockstream and across the width of the stock stream for generating a firstsubstantially uniform pattern of small scale turbulence of a first orderof magnitude in the stream, a second substantially greater multiplicityof spaced generally cylindrical rods downstream from said firstmultiplicity and substantially smaller in size extending from one ofsaid walls substantially the depth of the stock stream and across thewidth of the stock stream for generating a second substantially uniformpattern of smaller scale turbulence in the stream and a perforated plateextending transversely to the stock stream flow upstream from said firstmultiplicity for converting the stock stream under pressure to aplurality of high speed jets and said perforations being aligned withsaid first multiplicity to impinge the jets against the rods thereof,each of said second multiplicity rods being secured to one wall andhaving an upstream face extending downstream to define an obtuse anglewith the stock stream fiow direction of to to terminate closely spacedfrom the opposite wall, the improvement of each such upstream rod facehaving a longitudinal groove therein to minimize stapling of fibrousstock elements to the face of the rod.

2. In a tapered approach to a paper machine slice opening defined byconverging top and bottom walls for flowing a stock stream filling suchtapered approach through the slice opening and on to a forming surfacecomprising said stock stream flowing through the approach in a generallyrectilinear direction aimed at the slice opening, a plurality of spacedtransversely extending turbulence generating rod banks with each bankspaced downstream from its immediate upstream bank to receive turbulencetherefrom in partial decay, the downstream-most bank being spacedupstream from the slice opening to permit partial decay of its generatedturbulence ahead of the slice opening, and a plate upstream of theupstream-most bank with perforations aligned with the rods thereof toimpinge jets of stock thereagainst, each rod bank in downstreamsuccession being formed of successively smaller rods with successivelysmaller spaces therebetween for generation of successively smaller scaleturbulence in the stock and each of the rods in the downstream-most rodbanks extending at a downstream slant from one wall to closely spacedrelation from the opposite wall, the improvement of each rod having theslanted upstream face thereof defining a longitudinally aligned shallowrecess to minimize stapling of the fibrous stock elements to the face ofthe rod.

3. In a tapered approach to a paper machine slice opening defined byconverging top and bottom walls for flowing a stock stream filling suchtapered approach through the slice opening and on to a forming surfacecomprising said stock stream flowing through the approach in a generallyrectilinear direction aimed at the slice opening, a plurality of spacedtransversely extending turbulence generating rod banks with each bankspaced downstream from its immediate upstream bank to receive turbulencetherefrom in partial decay, the downstream-most bank being spacedupstream from the slice opening to permit partial decay of its generatedturbulence ahead of the slice opening, each rod bank in downstreamsuccession being formed of successively smaller rods with successivelysmaller spacers therebetween for generation of successively smallerscale turbulence in the stock and each of the rods in thedownstream-most rod banks extending at a downstream slant from one wallto closely spaced relation from the opposite wall, the improvement ofeach rod having the slanted upstream face thereof defining alongitudinally aligned shallow recess to minimize stapling of thefibrous stock elements to the face of the rod.

References Cited by the Examiner UNITED STATES PATENTS 1,909,150 5/ 1933Bell-Irving et al 162-347 2,881,674 4/1959 Johnson et a1 1622162,929,449 3/ 1960 Mardon et a1. 162338 3,014,527 12/1961 Beachler162-347 3,092,540 6/1963 Parker 162-343 FOREIGN PATENTS 370,422 2/ 1923Germany.

DONALL H. SYLVESTER, Primary Examiner.

MORRIS O. WOLK, Examiner.

3. IN A TAPERED APPROACH TO A PAPER MACHINE SLICE OPENING DEFINED BYCONVERGING TOP AND BOTTOM WALLS FOR FLOWING A STOCK STREAM FILLING SUCHTAPERED APPROACH THROUGH THE SLICE OPENING AND ON TO A FORMING SURFACECOMPRISING SAID STOCK STREAM FLOWING THROUGH THE APPROACH IN A GENERALLYRECTILINEAR DIRECTION AIMED AT THE SLICE OPENING, A PLURALITY OF SPACEDTRANSVERSELY EXTENDING TURBULENCE GENERATING ROD BANKS WITH EACH BANKSPACED DOWNSTREAM FROM ITS IMMEDIATE UPSTREAM BANK TO RECEIVE TURBULENCETHEREFROM IN PARTIAL DECAY, THE DOWNSTREAM-MOST BANK BEING SPACEDUPSTREAM FROM THE SLICE OPENING TO PERMIT PARTIAL DECAY OF ITS GENERATEDTURBULENCE AHEAD OF THE SLICE OPENING, EACH ROD BANK IN DOWNSTREAMSUCCESSION BEING FORMED OF SUCCESSIVELY SMALLER RODS WITH SUCCESSIVELYSMALLER SPACERS THEREBETWEEN FOR GENERATION OF SUCCESSIVELY SMALLERSCALE TURBULENCE IN THE STOCK AND EACH OF THE RODS IN THEDOWNSTREAM-MOST ROD BANKS EXTENDING AT A DOWNSTREAM SLANT FROM ONE WALLTO CLOSELY SPACED RELATION FROM THE OPPOSITE WALL, THE IMPROVEMENT OFEACH ROD HAVING THE SLANTED UPSTREAM FACE THEREOF DEFINING ALONGITUDINALLY ALIGNED SHALLOW RECESS TO MINIMIZE STAPLING OF THEFIBROUS STOCK ELEMENTS TO THE FACE OF THE ROD.